Private equity firms have found an exciting industry to invest in: themselves.

Some firms have raised billions of dollars to take general partner stakes in other private equity players. Since 2007, funds targeting GP stakes have raised more than $17bn and have plans to raise a further $20bn, according to data from Pitchbook. Among those trying this strategy are Blackstone, Neuberger Berman’s Dyal Capital Partners and Goldman Sachs’s Petershill.